Bioreactor Gas Feed Strategy for High-Rate Methane Production

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Solution Overview

Problem

Current methods for converting hydrogen and carbon dioxide into methane suffer from low energy recovery rates, high production costs, and inefficiencies, limiting their economic viability and widespread applicability, especially when using renewable energy sources.

Innovation Solution

A method involving a reaction vessel with a gas feed rate of at least 1.2 vvm of hydrogen and carbon dioxide and an absolute pressure of at least 5.0 bar, optimized by controlling the partial pressure ratio of hydrogen to carbon dioxide, enhances volumetric productivity and methane concentration, using methanogenic microorganisms to produce methane efficiently.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If conventional methods are used to convert hydrogen and carbon dioxide into methane, then the process can proceed with standard equipment, but the volumetric productivity and energy recovery rate remain low

Engineering Contradiction:
Improvevolumetric productivityVSAvoidprocess complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent applies parameter changes by increasing the gas feed rate to at least 1.2 vvm and maintaining absolute pressure at least 5.0 bar, which significantly improves volumetric productivity and energy recovery rate compared to conventional low-pressure, low-feed-rate operations

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs preliminary action by pre-mixing hydrogen and carbon dioxide in a specific ratio (at least 4:1 volumetric ratio) before introduction into the reactor, ensuring optimal conditions for methanogenic microorganisms to achieve high productivity from the start

Inventive Principle:
Principle #10Preliminary action

2Productivity

If high gas feed rates are used to increase productivity, then volumetric productivity improves, but the risk of incomplete conversion and waste gas emission increases

Engineering Contradiction:
Improvevolumetric productivityVSAvoidenergy loss
Core Design Contradiction:
ProductivityVSLoss of energy

Solution Approach 1:

The patent implements feedback control by continuously monitoring the composition of the gas mixture and adjusting operational parameters to maintain optimal conversion efficiency, ensuring that high feed rates do not lead to excessive energy loss through incomplete conversion

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent applies partial action by using a gas feed rate of at least 1.2 vvm (excessive compared to conventional methods) while compensating through pressure control and ratio optimization to ensure complete conversion, thereby achieving high productivity without significant energy loss

Inventive Principle:
Principle #16Partial or excessive action

3Productivity

If the partial pressure ratio of hydrogen to carbon dioxide is not optimized, then the process is simpler to operate, but the methane concentration and productivity decrease

Engineering Contradiction:
Improvevolumetric productivityVSAvoidoperational simplicity
Core Design Contradiction:
ProductivityVSEase of operation

Solution Approach 1:

The patent applies preliminary action by pre-mixing hydrogen and carbon dioxide in a specific volumetric ratio of at least 4:1 before introduction into the reactor, ensuring optimal partial pressure conditions for maximum methane production without requiring complex real-time adjustments during operation

Inventive Principle:
Principle #10Preliminary action

4Object-affected harmful factors

If renewable energy sources are used to produce hydrogen and carbon dioxide, then environmental friendliness improves, but the overall energy recovery rate remains low due to conversion inefficiencies

Engineering Contradiction:
Improvegreenhouse gas emissionsVSAvoidenergy recovery rate
Core Design Contradiction:
Object-affected harmful factorsVSLoss of energy

Solution Approach 1:

The patent implements continuity of useful action by maintaining continuous operation at high gas feed rates (at least 1.2 vvm) with optimized pressure and ratio conditions, ensuring that renewable energy inputs are continuously and efficiently converted to methane with minimal loss, achieving both environmental sustainability and high energy recovery

Inventive Principle:
Principle #20Continuity of useful action

Solution Approach 2:

The patent applies parameter changes by operating at elevated pressure (at least 5.0 bar absolute) and high feed rates, which significantly improves the energy recovery rate of the conversion process, making renewable energy-based methane production economically and environmentally viable

Inventive Principle:
Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach significantly increases the volumetric productivity and methane concentration, making the process economically feasible and environmentally friendly by utilizing renewable energy sources and recycling waste carbon dioxide, thus reducing greenhouse gas emissions.

Implementation Method 1

converting hydrogen and carbon dioxide into methane by methanogenic microorganisms

Methodology Applied
Scientific EffectMethanogenesis: Anaerobic Digestion

Implementation Method 2

a gas feed rate of at least 1.2 vvm of hydrogen and carbon dioxide and an absolute pressure of at least 5.0 bar

Methodology Applied
Scientific EffectGas flow and pressure control:

Data Source

PatentEP2872637B1Method and system for producing methane using high gas feed rates
Publication Date: 2025.11.26 KRAJETE
  • EP2872637B1 patent drawingFigure 1
  • EP2872637B1 patent drawingFigure 2
  • EP2872637B1 patent drawingFigure 3

AI summary

The present invention provides a method and system for producing methane. The method comprises contacting methanogenic microorganisms in a reaction vessel with hydrogen and carbon dioxide, wherein the gas feed rate of hydrogen and carbon dioxide into the reaction vessel is at least 1 vvm in total or at least 1.2 vvm in total. The invention further provides a system for producing methane comprising at least one device for generating electric energy from a renewable and/or non-renewable energy source, at least one device for producing hydrogen and/or oxygen by the electrolysis of water and/or brine, and at least one bioreactor comprising a reaction vessel suitable for growing, fermenting and/or culturing methanogenic microorganisms and at least one device for providing a gas feed of hydrogen and carbon dioxide into the reaction vessel.